In his letter, Nichols alleged that gun dealer Roger Moore -- who provided key testimony for the prosecution in Nichols' 1997 conspiracy trial -- was an FBI "provocateur" who sold explosives to Timothy McVeigh, who was executed in 2001 as primary perpetrator of the April 19, 1995 bombing that killed 168.

In a crucial new allegation, however, Nichols wrote to Trentadue that Moore also sold bomb-making material to a group of white supremacist bank robbers long suspected of playing a role in the bombing -- the Midwest Bank Robbers, also known as the Aryan Republican Army.

"Roger Moore is a government provocateur who not only provided Timothy McVeigh with Kinestik (a 2-part binary explosive) but he also provided others with explosive components, including those with the Midwest Bank Robbers," Nichols wrote.

In a September 2006 letter to attorney Jesse Trentadue, the convicted Oklahoma City bombing conspirator claimed that the Bureau of Prisons has prevented him from speaking with the press. Trentadue provided a copy of the letter to INTELWIRE after Nichols agreed to its release in the media. Click here to read the letter.

Nichols is serving out a life sentence in a maximum security cell block alongside some of the world's most dangerous criminals, including Ramzi Yousef, Unabomber Theodore Kaczynski and mob informant Gregory Scarpa Jr.

Nichols first made allegations about Moore's role as an explosives supplier in a 2005 conversation with fellow inmate Scarpa, who passed the information to both the FBI and independent investigators. ( Click here for details.)

At that time, Nichols described a hidden stash of weapons under his Herington, Kansas home, which he said were provided by Moore. The FBI -- which missed the stash in its initial investigation -- eventually dispatched agents to the house, who confirmed that the material matched Nichols' description.

Moore has never been charged, or named as a informant, in connection with the Oklahoma City bombing and has denied any involvement in the bombing.

Moore was called to testify in Nichols' trial in relation to a robbery of his Arkansas ranch, which prosecutors claimed was used to fund the bombing plot. Nichols apparently believed Moore's fingerprints would be found on the material hidden in his house, but the FBI has not confirmed whether new prints were found.

Nichols was alleged to have committed the robbery, but other individuals associated with McVeigh have suggested that the robber was actually Richard Guthrie, one of the bank robbers. Moore never claimed to make a positive identification of Nichols, but items stolen from Moore were found in a Las Vegas storage locker maintained by Nichols. (Nichols reportedly later admitted he had carried out the robbery.)

Nichols told Trentadue he has been prevented from talking with the press, including investigative reporters with CBS news program 60 Minutes. He claimed 60 Minutes had been trying to arrange an interview with him for two years. Nichols said he sent 60 Minutes a nine-page letter outlining "a general picture of some of the connections in the OKC bombing that don't paint a pretty picture for the FBI."

THE KENNETH TRENTADUE MURDER

Jesse Trentadue, a Salt Lake City attorney, started investigating the Oklahoma City bombing after the hanging death of his brother, Kenneth Trentadue, while in federal custody on Aug. 21, 1995.

In the new letter, Nichols claimed to have information about Kenneth Trentadue's death.

"I too believe your brother was murdered, but I cannot provide you with physical proof of such," Nichols wrote. "However, I have talked with an individual who was there at that time, and even talked with your brother, but he's afraid to come forward."

Kenneth Trentadue's death was initially declared a suicide by prison officials, but the family discovered signs of extensive injuries when preparing him for burial. The family was eventually awarded more than $1 million after winning a wrongful death suit against the government.

Jesse Trentadue believes his brother was murdered in a case of mistaken identity by unknown individuals who believed Kenneth Trentadue was actually Richard Guthrie, one of the Midwest Bank Robbers.

Trentadue and Guthrie had very similar physical descriptions and both men closely resembled a description of a never-apprehended suspect known popularly as "John Doe 2."

Jesse Trentadue sued the FBI under the Freedom of Information Act to force the release of documents concerning the investigation. During the ensuing court battle, the court found that the FBI obstructed the request at various stages and misrepresented the available material.

"As you yourself have personally experienced, the FBI and DOJ are very powerful, very stubborn and will go to any lengths to keep not only your brother's murder covered up, but also the truth of the OKC bombing," Nichols wrote.

"I am not surprised that the Department of Justice is trying so hard to keep Terry Nichols from exposing the federal government's complicity in the Oklahoma City Bombing by denying him all contact with the media," Jesse Trentadue said today via e-mail. Trentadue said he believes Nichols' claims to be true and that his brother was murdered for his resemblance to Guthrie.

In July 1996, Guthrie himself was found hanged to death in his cell, in a manner reminiscent of the death of Kenneth Trentadue. INTELWIRE has obtained Guthrie's autopsy results and records pertaining to his death, which was ruled a suicide.

As a result of Trentadue's lawsuit, the FBI released 100 pages of documents outlining possible links between McVeigh, the Midwest Bank Robbers and other the white supremacists earlier this year.